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Re: Absolute Time

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Posted by Zephram Cochrane/">Zephram Cochrane on December 19, 1999 20:36:19 UTC

: : : : I have been looking at the theory of relativity and was wondering about the idea, that as an object is traveling at or near the speed of light, or is accelerated (a force acting on the object apears to be arbitrary) at or near the speed of light an observer will observe the time of the object slow down. I dont think this is right though. Given a person (person A) in a space that has no sides, celling or floor, and another person(person B) is traveling at or near the speed of light(for the rest of the story I will refer to this speed as "speed C" in order to not type repetitive information) in the same space. Each person has a clock. Person A observes person B traveling at speed C an acording to Einestin's theory, Person A will see person B's clock to fall behind his own. Acording to relativity, person B will see person A travel at speed C realitive to himself, hence he will expirience person A's clock to fall behind his own. Now, when the two clocks are brought next to each other, they will have to bee the same. I am not sure how this applies, and I would be very thankfull for any help on clearing this up.

: : In order to bring the clocks back together, one or both of the clocks must undergo acceleration. Lets say clock A is left alone and a force is applied to clock B to accelerate its motion back toward clock A. During this acceleration the observer carrying clock B no longer observes clock a to be running slower, but instead observed an increased rate of clock A. This can be understood in a few ways, the simplest is to realize that the accelerated frame of B can be considered to be a transition between different inertial frames which each have different standards for simultaneity. In this scenario when the two clocks are brought back together clock A will have more time clocked than clock B. If instead of applying the force to B you applied it to A then B would have more time recorded than A. If they were pushed symmetrically then they read the same time when back together. This is why it is said that a space traveler traveling near light speeds could go to another star and back in what would be a few minutes although by the time the ship arrived back at earth many years would have gone by for those on earth.

: But relative to each other, isn't the same thing happening to both clocks with the exception of a force only being excerted on one clock.

The acceleration due to the force it the difference.

:If clock A is set to the exact time observed on clock B who is one light-hour away, I agree that clock B will have more time recorded then clock A. Is this not time-dialation?

I thought you wanted to start the situation with them together. Starting them apart is more complicated because you have to choose a frame of reference in order to determine that they are one light year apart and set their times and when you switch to one of the clock's frames you must realize that because of the lack of simultaneity between the frames the clocks are not synchronized. Simultaneity itself is relative, not absolute. The same goes for the 1 ly distance between them.

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